Radio signaling



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RADIQ SIGNALING Filed Jan. l5, 1929 f1@ gw QETECTGF? fw/ff@ @Mq Patented Oct. 25, 1932 ,UNITED STATES PATENT OFFICE WILLIAM R. BLAIR ANI) LOUIS COHEN, F WASHINGTON, DISTRICT OF COLUMBIA i RADIO SIGNALIN'G Application filed January 15, 1929. Serial No. 332,624.

(GRANTED UNDER THE ACT 0F MARCH 3, 1883, AS AMENDED APRIL S0, 1928; 370 O.l G. 757) The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to us of any royalty thereon.

In pending applications Serial Numbers 294,742, 'filed July 28, 1928; 808,087, tiled August 80, 1928 g 821,688, iled November 24, 1928; and in Patents 1,818,568, dated July 7, y 1981; 1,854,448, dated April 19, 1982, and 1,857,859, dated May 10, 1982, novel methods for the reception and transmission of radio signals are described in which wave conductors in various circuit combinations are employed. In these inventions a new method of tuning is introduced based upon the use of wave conductors, that is conductors of distributed inductances and capacities on which wave developments are effected. A wave conductor comprises a solenoid'al coil suitably designed in the matter of diameter and number of turns of wire and placed in proximity to a metal plate which may be either grounded or ungrounded. An adjustment of the wave conductor is effected by varying the d'istance separation of the solenoidal coil from the metal plate thereby varying the distrib'- uted capacity and distributed inductance, and consequently its adjustment in relation to the frequencies of the signals transmitted or received. Using such wave conductors in the various circuit combinations described in the pending patent applications referred to above, important'results are obtained in the matter of sharpness of tuning both in the transmission and the reception of signals and also adaptable for multiplex transmission and reception of radio signals.

The invention described in this application has reference to the same general method providing however, important modifications by which still further improvements are obtained particularly in the matter of sharpness of tuning.

The scope and' character of this invention can be best understood by referring to the accompanying drawing which form a part of this specification in which- Y Figure 1 shows an embodiment of the invention adapted for the reception of radio signals in which the metal plate of the wave conductor is connected` to one terminal or the .primary of a receiving circuit system. Figure 2 is a modification in which the metal plate lof the wave conductor is brought into electrostatic inductive relation with the receiving system.

Figure 8 is another modification in which both terminals of primary of a receiving- Having particular reference to the drawing in which similar numbers designate similar parts throughout, in Figure 1 the antenna designated by-l is connected to terminal 2 of coil 8 which together with metal plate 4 constitutes a wave conductor, that is a conductor .of suicient length electrically to insure a wave development on it. VThe electrical length is adjustable by the variation of the distance separation of the coil 3 from the metal plate 4. The metal plate 4 is connected through lead 5 to one terminal of primary coil 7 which is coupled to the tuned circuit 8 9. The terminals 10-11 of condenser 9 are connected to amplifier and detector in the usual way. The metal plate 4 of the wave conductor is grounded at 6. With this circuit system when suitably adjusted for any particular signal frequency which it is desired to receive, a remarkable high degree of selectivity and freedom from interferences is obtained. Thevwave conductor 8`4 must be suitably designed in the vmatter of diameter of coil and number of turns of wire and means for varyingwithin proper limits the distance separation ot the coil 8 from the metal plate 4, so that for the frequency range for which its' use is intended, an adjustment could be made to secure the development of the proper fraction of Wave lengths. To be exact, it is believed that the best adjustment is that of a quarter Wave length of the signals desired to be received. In practice an adjustment is made by the variation of the distance separation of coil 3 from metal plate 4; the signal is of maximum intensity at one oiut of the adjustment. The circuit 8-9 is' tuned in the usual Way.

It would seem that in accordance with established theory the circuit system described in Fi re 1 should be very inefficient giving practically no signal at all in the receiving circuit since the primary 7 is connected only at o ne point which is grounded at 6 through the metal plate 4, but the fact is that the system is very eiicient for the reception of radio signals. We have operated the circuit system for sometime receiving signals from many distant stations giving good volume and very high selectivity. IVe do not oii'er here any theoretical explanation for the operation of this circuit system.

The modification shown in Figure 2 differs only from that of Figure 1 in that the grounded metal plate 4 of the Wave conductor is connected through the lead 5 to a small metal plate 12 which is placed in proximity to coil 8, and by electrostatic induction acts on the tuned receiving circuit 8-9. The method of operation is precisely the same as that described in connection with Figure 1, the coil 7 of Figure 1 being replaced here by the metal plate 12 both functioning in the same Way acting electrostatically on the tuned circuit.

Another modification is shown in Figure 3 in which both terminals of primary coil 13 are connected to the grounded metal plate 4. In this arrangement the action from the primary 13 on the tuned circuit 8-9 is probably mixed, electro-magnetic and electrostatic. Somewhat better results are obtained when the points 14 and 15 at which the terminals of coil 13 connect to metal plate 4 are as far apart as possible on the metal plate.

In Figure 4 a modification is shown in which the metal plate 4 of the wave conductor is directly connected through the lead 17 to the tuned circuit 8--9 of the receiving system. As in the arrangements of the previous figures the metal plate 4 is grounded at 6.

Figure 5 shows an embodiment of the invention in its adaptability for the transmission of signals. 18 designates a transmitter, preferably of the vacuum tube type, which is associated with the tuned circuit comprising inductance 19 and condenser 20. The coil 21 of the wave conductor is connected at 3() to the 'tuned circuit 19-20 and the metal plate 22 of the wave conductor is connected through tl'ie lead 23 to another tuned circuit 24-25 which is coupled to the antenna 27 through the transformer 25-26. The antenna may be tuned if desired though We find that elicient transmission is obtained by using an untuned antenna. It is obvious of course that by using an untuned antenna several transmitters operating on diii'erent frequencies may be coupled to the same antenna affording thereby a means or'multiplex transmission.

The embodiment ofthe invention shown in Figure 6 differs only from Figure 5 in that the metal plate 22 of the wave conductor is grounded at 29. By this modification of grounding the plate 22 the sharpness of tuninfrr of the system is very much enhanced.

in all of the modifications of the invention described in this application the basic idea involved is the use of an adjustable Wave conductor linking the energy source with a responsive oscillating circuit system, transmittin g the energy from one to the other through a Wave conductor. The coupling element, which is the Wave conductor, is in itself a tuned device the tuning of which is accomplished through the variation of its distributed capacity and distributed inductance introducing thereby a novel principle in tuning. By the proper adjustment of the Wave conductor and the oscillating circuit system in relation to the frequency remarkably sharp tuning is obtained. In the use of the system for the reception of signals, great freedom from interferences and static disturbances is obtained. v

We claim: Y

1. In a system or the reception of radio signals comprising an antenna, a. wave conductor and a receiving circuit, said Wave conductor consisting of a solenoidal coil placed in proximity to a grounded metal plate, the antenna being connected to one terminal of the coil of said wave conductor, and the grounded metal plate of said Wave conductor being connected to one terminal of the primary of said receiving circuit system, the secondary of said receiving circuit being operatively associated with detecting and ampliying means.

2. In a systemy for the reception of radio signals comprising with an antenna, and a tuned receiving circuit, a tuned Wave conductor electrically linking said antenna and said tuned receiving circuit. said conductor comprising a coil connected to the said antenna, and a metal plate brought into electrostatic relation to the said tuned circuit, the metal plate of said Wave conductor being grounded.

3. In a system for the reception of radio signals, comprising with an antenna, and a timed receiving circuit; a tuned wave conductor electrically linking said antenna and said tuned receiving circuit, said conductor comprising a.y coil connected to the said antenna, and a metal plate brought into electrostatic relation to the said tuned circuit, the metal plate of said wave conductor being grounded, and the Wave conductor being tuned by varying the distance separation of the coil from the metal plate of the said Wave conductor.

4. In a system for the reception of radio signals, comprising'an antenna, a Wave conductor, and -a receiving circuit operatively associated With detecting and amplifying means, the said Wave conductor consisting of a Wave coil and metal plate, the' said metal plate being grounded, one end of the said Wave conductor being connected to the an tenna and the said receiving circuit being associated electrically With the grounded metal plate.

5. In a system for the reception of radio signals, comprising an antenna, a Wave conductor, and a receiving circuit operatively associated with detecting and amplifying means, the said Wave conductor consisting of a Wave coil and grounded metal plate, the distance separation between said Wave coil and said grounded metal plate being adjustable to bring it into resonance relation With the frequency of the signal which it is desired to receive, one end of the said Wave conductor being connected Ito the antenna and the said receiving circuit being associated electrically With the grounded metal plate.

In testimony whereof We aiiix our signatures.

WILLIAM R. BLAIR. LOUIS COI-IEN.

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